Lecture Notes on Fossils and Population Dynamics

These flashcards cover key terms and concepts related to fossils, population dynamics, and natural selection as outlined in the lecture notes.

Radiometric Dating

A method used to determine the age of fossils by measuring the decay rate of radioactive isotopes.

Half-Life

The time required for half of the radioactive isotopes in a sample to decay.

Carbon-14

A radioactive isotope used for dating relatively young fossils, with a half-life of 5,730 years.

Uranium

A radioactive isotope used for dating ancient fossils, with a half-life of 4.5 billion years.

Gene Flow

The movement of alleles between populations when individuals, seeds, pollen, or gametes move and reproduce in a new population.

Directional Selection

A type of natural selection that favors individuals exhibiting one extreme of a phenotype range.

Disruptive Selection

Natural selection that favors variants at both ends of the distribution, leading to two or more contrasting phenotypes.

Stabilizing Selection

Natural selection that removes extreme variants from the population and preserves intermediate types.

Frequency Dependent Selection

A form of selection where the fitness of a phenotype depends on its frequency relative to other phenotypes in a population.

Relative Fitness

A measure of an individual's reproductive success compared to others in the population.

Density

The number of individuals per unit area or volume in a population.

Dispersion

The pattern of spacing among individuals within the boundaries of a population.

Demography

The study of key characteristics of populations and how they change over time.

Cohort

A group of individuals of the same age, from birth until all individuals are dead.

Survivorship Curve

A plot representing the proportion or number of a cohort still alive at each age.

K-Selection

Selection for traits that are advantageous at high population densities.

R-Selection

Selection for traits that maximize reproductive success in uncrowded environments.

Density Independent

A birth or death rate that does not change with population density.

Density Dependent

A death rate that increases with population density or a birth rate that falls with increasing density.

Population Dynamics

Fluctuations in population size from year to year or place to place due to various factors.

Meta-Population

A group of local populations linked by immigration and emigration.